How Does Glucose Move into a Cell?

Eat a bowl of cereal or a piece of fruit and your body will convert the carbohydrates in your meal to glucose--the form of sugar cells in the body rely on for quick energy. Glucose circulates through the blood stream, powering your muscles, organs, and brain. But how exactly does your body use glucose?

Eat this to generate loads of glucose (Image: DAJ/amana images/Getty Images)

The Transporters

Your body relies on molecules called glucose transporters (GLUT is the scientific term) to deliver the sugar to cells. GLUT molecules tend to specialize: GLUT2, for example, delivers glucose to the digestive tract, liver, and pancreas; GLUT3 keeps the central nervous system and the brain running; GLUT4 serves the heart, muscles and fat cells. And GLUT1? It's a general transporter that can fill in where needed.

Binding

When cells require energy, the GLUT molecule on the cell's surface will bind with blood glucose and usher it into the cell. After reaching the inside of the cell, the cells machinery converts the sugar into energy.

Insulin

You've probably heard about the hormone insulin in connection with blood sugar before: After all, many people with diabetes rely on insulin shots to help control their blood sugar. Insulin primarily assists GLUT4--the transporter that serves muscle and fat cells. Insulin can boost the number of transponders on fat cells especially, and it can increase the rate at which fat cells' transponders bind with sugar. When you have high levels of glucose in the blood, insulin can urge fat cells to absorb the excess sugar and store it as fat.

The Hazard of too Much Sugar

People who overeat carbohydrate-rich foods like breads, pasta, and cereal or regularly down colas and other sweet drinks, can overtax the body's ability to process glucose. The pancreas--which produces insulin--can fail to secrete enough of the hormone to meet the body's needs. Insulin-resistance is another danger: Glucose transporters--especially GLUT4--can fail to respond to to insulin's message to process more glucose. A failing pancreas and insulin-resistance can lead to diabetes--which is why it's so important to limit the amount of sugar in your diet.